We have have a customer that uses an Bewacom (http://www.bewator.com/se/products/index.xml/AC/AC_DEP/AC_DEP_BEWACOM/se85)
it is now attached to an ATA186-L2. The bewacom listens to DTMF 5, then it opens the door. I have got it to work with the stationary phones, for example 7912, 7940, 7960, but NOT with 7920.
I guess the Bewacom does not get an clear DTMF 5.
And i thought i would get it work with an IPCC script, so the person in the reception could open the door with her 7920. But the bewacom does not understand the DTMF 5 from the IPCC script either.
Anyone who have done anything like this?